Servo Erector Set 3-D Models Database

Lynxmotion Servo Erector Set
221

Gentle persons:

I just downloaded most of the SES database entries. First, let me say I am grateful to all those who did the hard work to create these models. I hope to reciprocate. The following represents nothing more than a little nitpicking on my part.

It seems that the entries for ASB-22 and ASB-24 are duplicates of the entry for ASB-21, image and all. Just for grins, I tried to reach models for ASB-22 and ASB-24 by changing the ASB-21 file names appropriately. No joy. I guess these parts haven’t been modeled yet(?).

Many of the SES models are available in different file formats, often associated with different contributors. I suggest it would be useful to include an additional datum indicating model parentage.

For example, I look at the first entry, for “Servo [Standard Size Hitec]”, and see four files:

o [Alibre Designs] by linuxguy
o .igs] by linuxguy
o [Solidworks 2005] by ???
o [Step AP214] by linuxguy

It might seem reasonable to assume that the Alibre Design, IGES, and STEP files all represent a model that was created in Alibre Design (but you know what they say about assume). Then, does the Solidworks file represent the same model (re)created in Solidworks by importing one of linuxguy’s files or does it represent a different model created directly in Solidworks (or, vice versa, is the Alibre Design model new or a descendent of the Solidworks model)? For simplicity, I haven’t included the possibility that third-party software products, of which there are many, were used to translate among the modeling file formats.

For simple parts this matters very little but for more complicated parts and for assemblies it can matter a great deal in terms of what one can do with the result (I still bear scars from some disasters in my former professional life to prove it).

Even a simple notation like N for “new” model, T[modelx] for “translated” from modelx and B[modelx] for “based on” modelx, in the case that the model was rebuilt in the new system, would be useful.

Like I said, these musings are mere nitpicks. I’m grateful I have available this “kit of part models” with which I can quickly build up and test my ideas for a robot. Thanks.

Regards,
Kent

PS - for some CAD file formats one can capture the same information directly in the file but this isn’t generally so; besides, one ought to be able to find out without having to load the file into an appropriate system.

PPS - Now that I’m retired, I’m pretty much using only Alibre Design because of my new-found appreciation of the cost of software. Gone are the days when I had one of every commercial 3D modeling system at my fingertips!

222

I’m not sure I understand what you are asking but the 3D files were not converted from anything. The models were created from scratch using 2D drawings with the dimensions. This collection of files is strictly a voluntary effort by the Lynxmotion community to offer builders a way to experiment with different design configurations using any modeling program they prefer. The .IGS extension refers to “Initial Graphics Exchange Specification” it’s a neutral data format that allows the digital exchange of information among Computer-aided design (CAD) systems. This format is very popular with many many CAD programs and it’s a great cross-platform format.

223

I’ll look into this - most likely I goofed something up while uploading. Thanks for pointing it out.

While I understand what you’re asking, there’s just no possible way for me to include this information. All of the models we have were provided by different people who volunteered to do it, and I have no history regarding who used which program. Sorry.

224

Sorry I didn’t make myself clear, Mike. I understand how the CAD models were created and I hope to contribute some myself. My point is that all the files on this site are not CAD models themselves (which reside only within a given CAD system) but data exchange files (which are external “serializations” of the model data based on a set of rules for mapping to and from the serialization).

Making a distinction between the CAD model and the data exchange file may seem like a pointless semantic argument but it is important to some of us bitheads (I was the editor of IGES V4.0, V5.0, and V5.1, as well as the co-editor of the initial release of STEP. Each of these represents thousands of hours of committee work by an international community of bitheads.) Essentially, it is the same distinction that is made in the philosophical remark “the map is not the territory.”

I’m please to read your remark that IGES is a great cross-platform format. That was not always so. Thanks to the US DoD and tons of financial support to CAD vendors through the CALS program, it is now.

Thanks for taking the time to reply.

Regards,
Kent

225

Looking at your reply, Beth, I realize I should have broken my suggestion into two parts, with only the second part touching on your role. I intended no criticism of the work already done by you or the modelers. As I said, I’ve downloaded all the files to use in my own design efforts, grateful that I don’t have to start from scratch, taking off measurements from parts I buy and begging drawings for parts I don’t already have.

In two parts, the suggestion is

  1. It would seem to be useful, going forward, for submitters of files to indicate model parentage. Obviously this is voluntary; others will continue to use the files with or without.
  2. Assuming submitters do this, the site administrator (aka you :smiley:) would have to find a way to include this information in the database and in the html representation on the website.

This is just MTCW (my two cents worth) and you know how much two cents buys these days.

I look forward to downloading the missing files.

Thanks for your efforts and your reply.

Regards,
Kent

226

All the 3D models I create are done with Alibre Design, and that my native format. Other formats I created are exported from the main model.

8-Dale

227

Gentle persons:

Further my messages about the origins of the database model files—

Including screws and washers, I have downloaded 78 models in Alibre Design file format. Of these, 30 began life as STEP files brought in from somewhere, as can be seen by opening them in AD and looking at the Design Explorer. For the files I’m talking about, one will see the entry “Imported STEP file” under Features (confession: after opening the first file, I used a tool to find all the part files containing that string). If anyone is interested, I can post a list of these files.

What this means practically is that the features have been stripped of constraints. For example, a hole is imported as a pair of semi-cylindrical surfaces explicitly defined by faces and edges. This pair is readily recognized as a hole by a human looking at the display, but not by AD looking at the model geometry.

Whether this is a problem or a non-issue depends on what one intends to do with the models. In my case, I want to use the full capability of AD to build up assemblies from catalog parts. To do so, I’ll have to add back to the part models the “intelligent” features I need using the database files as templates. A nuisance maybe but far better than starting from scratch.

Regarding my message “Problem with servo.AD_PRT files” elsewhere, I think I’ve found a solution and I’ll post it when I’m convinced it’ll work for others.

Regards,
Kent

PS - I apologize for my fitful participation in the Lynxmotion forum. Robotics is fun, but my wife’s medical condition takes precedence.

228

Why would you be using the STEP format if you have Alibre Design? For AD you should be using the *.AD_PRT format files, which have all the needed dimensions included. Please download the Alibre Design formats for AD. :slight_smile: All other formats created (exported from) AD, will not have any dimensions included, as you have noticed, because they are not native formats for AD.

8-Dale

229

Sorry for not being sufficiently clear.

I was downloading only .AD_PRT files from the SES 3D Model database. On the database web page, these are identified as Alibre Design] files.The comments in my previous message follow from examination of these files, not any of the files in other formats.

Assuming you have Alibre Design at your fingertips, compare what you get when you download and open the file asb-201.AD_PRT (which has constraint-based dimensions, as shown in the features list) versus asb-02.AD_PRT (which does not; the features list shows “Imported STEP file”).

Regards,
Kent

230

I just looked at the ASB-02.AD_PRT file, and it is definitely NOT as Alibre Design format file. I don’t know what format it is from loading it into Alibre Design, but it is not a native Alibre Design file and I did not create it as far as I can remember.

Note to Beth: The ASB-02.AD_PRT file should be removed from the model database.

8-Dale

231

I must be going blind. I finally noticed that you are “linuxguy”, the source of many files in the database. Sorry it took me so long (sometimes I can’t see the forest for the trees!), but thanks for your work.

Before we start removing files piecemeal, let’s look at the big picture.

Of the *.AD_PRT files that I’ve downloaded, the following 29 exhibit the same “Imported STEP file” lineage:

HMSH-01.AD_PRT
ServoHornPlastic.AD_PRT
ahc-01.AD_PRT ahc-02.AD_PRT
arf-01.AD_PRT arf-02.AD_PRT
asb-02.AD_PRT asb-06.AD_PRT asb-09.AD_PRT asb-10.AD_PRT asb-11.AD_PRT
asb-12.AD_PRT asb-13.AD_PRT asb-14.AD_PRT asb-15.AD_PRT asb-16.AD_PRT
asb-17.AD_PRT asb-18.AD_PRT asb-19.AD_PRT asb-21.AD_PRT
at-01.AD_PRT at-02.AD_PRT at-03.AD_PRT at-04.AD_PRT at-05.AD_PRT at-06.AD_PRT
bbh-01.AD_PRT
hub-08.AD_PRT hub-09.AD_PRT

Interestingly, these all originate from your Alibre Design work, as a string search on “linuxguy” shows. One way for this to happen would be if your “native” files had been read into Alibre Design and then exported to STEP files, followed by importing the STEP files into new Alibre Design environments, and saving the resulting designs in AD_PRT format.

Four files that I downloaded originated with you and are still what you call “native” Alibre Design files:

asb-201.AD_PRT asb-202.AD_PRT
hub-12.AD_PRT hub-13.AD_PRT

Regards,
Kent

PS - The nomenclature of different modeling programs can get in the way of communications some times. What you called “dimension” in an earlier message is a specific kind of what I have been calling “feature constraint.” As another matter of nomenclature, although the files we are discussing no longer contain the feature constraints you created, they are valid Alibre Design format files. There’s nothing wrong with their model geometry except that it has become what one of my CAD-developer buddies calls “brain dead etch-a-sketch.”

232

forgive me if this has been asked…
does anyone have the assembly files for the HBKR-01 [Round Hexapod Chassis] in Alibre Design?
current formats are [Solidworks 2006] & [Step AP214]

also i cannot access the Standoffs [MM and MF] in Alibre Design either?

is there any format converters i can get hold of that will convert Solidworks & Step Assemblies to Alibre Design?

thanks.

233

Guilty as charged! Should I hide? :wink:

When I do a 3D design, I also export STEP and IGES formats from the original *.AD_PRT file. I archive the *.AD_PRT, *.STEP, and *.IGES files together and send them to Beth when I am happy with the design. If you load the *.AD_PRT files into Alibre Design, they should show all dimensions. If they don’t, there may be a problem between versions of the software. I’m still stuck back at v10.x here. I’m not sure I created all those models, so will have to check.

All of the models I created should have three formats - native AD, STEP, and IGES.

From a professional modeler, this may be true, but remember that many of us here are not professionals in the field (such as myself). I’ve taught myself everything I know about 3D modeling and definitely don’t have everything down well as would be required in a professional environment. However, I do the best I can to create models usable by others.

8-Dale

234

<…my quoted drivel deleted…>

8-Dale:

I think you’ve done very well indeed to have modeled all these parts and I’m grateful you shared them. I’ve just been trying to understand what is present in the models available in the database.

This discussion would be a lot easier if we were just chatting over beer without the Internet filter between us. I apologize for falling into my nauseatingly academic mode as I attempted to be precise in my description of what I found and what I thought might have caused it. My wife hates this mode, my kids hate this mode, my staff used to tolerate it because they liked the work (and the pay). Now that I’m retired, I guess I’m subconsciously looking for new victims :confused:

You raise an interesting point about a possible problem between versions of Alibre Design. I sure hope it turns out not to be so because I have models stashed away from earlier, non-robotic projects I did in older versions of AD that I’d hate to have to recreate.

It would be great if you could get a chance to download and check even just one of the models in question.

I had hoped by now to have recreated native AD models for some of the parts myself, but my wife’s increasingly precarious health has kept us both from the things we wanted to do. Maybe this summer…

Regards,
Kent

235

I did download a couple of models (ASB-04.AD_PRT and ASB-06.AD_PRT) and looked at them. In these, and I am sure other cases, these are just models I imported from other formats and exported to *.AD_PRT format. I did not actually create the models - I just exported them to make them easier for other AD users to use without having to import them. These models will not show any dimensions because they were not created natively with AD. This should be corrected by creating native AD models for these parts. My import/export was meant to be a stop gap until proper native AD models could be created for the parts. I’d love to see a complete set of native format AD models in the database.

8-Dale